From: DavMac AT iname DOT com (Davin McCall) Newsgroups: comp.os.msdos.djgpp Subject: Re: mem to mem DMA transfer Date: Mon, 14 Jun 1999 11:45:54 GMT Organization: Monash Uni Lines: 27 Distribution: world Message-ID: <3764ead7.31348820@newsserver.cc.monash.edu.au> References: <3764a2a7 DOT 0 AT 212 DOT 7 DOT 64 DOT 37> NNTP-Posting-Host: damcc5.halls.monash.edu.au X-Trace: towncrier.cc.monash.edu.au 929360714 1127 130.194.198.138 (14 Jun 1999 11:45:14 GMT) X-Complaints-To: abuse AT monash DOT edu DOT au NNTP-Posting-Date: 14 Jun 1999 11:45:14 GMT X-Newsreader: Forte Free Agent 1.1/32.230 To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Reply-To: djgpp AT delorie DOT com A while ago, I was trying to find info about doing this myself. I scanned documents from the web, found something that looked interesting, contacted the author and they told me they'd given up trying as it isn't the most efficient way to copy memory anyway (if memory reads/writes are being done, it's still taking up processor time: you might as well just do it in the conventional way). I also remember reading that the DMA chip itself is capable of mem-to-mem transfers, but in the PC the wiring makes this impossible. In any case, I never managed to do it. Davin. On Mon, 14 Jun 1999 08:37:34 +0200, "Max Breganze" wrote: >Do you think it's possible doing a DMA transfer from system mem to video mem >leaving the CPU free of doing something else in the meanwhile? >Some time ago I heard about this possibility for the screen update, but >someone said it's useless for many reason I don't remember. >Do you think it's possible and useful? >Please, give me your opinion and maybe some useful information about it. __________________________________________________________ *** davmac - sharkin'!! davmac AT iname DOT com *** my programming page: http://yoyo.cc.monash.edu.au/~davmac/